1. Field of the Invention
The present invention relates to a process for minimizing the formation of color during preparation of polyamides by ester-amine interchange and, more particularly, relates to the preparation of polyamides by ester-amine interchange in the presence of hypophosphorous acid.
2. Description of Related Art
Melt preparation of polyamides by amine ester interchange is known in the art, see Fox, et. al., U.S. Pat. No. 4,567,249, which is incorporated herein by reference. Although the aforementioned melt process has numerous advantages over prior salt process, the polyamides prepared by the melt process have often produced yellow-golden colored amorphous polyamides. This coloration may be at least partially attributable to oxidation of phenolic byproducts produced during the melt process.
It is an object of the present invention to provide an ester-amine interchange melt process which will produce amorphous polyamides having reduced coloration.